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  #ifndef QABSTRACTITEMMODEL_P_H
  #define QABSTRACTITEMMODEL_P_H
  
  //
  //  W A R N I N G
  //  -------------
  //
  // This file is not part of the Qt API.  It exists for the convenience
  // of QAbstractItemModel*.  This header file may change from version
  // to version without notice, or even be removed.
  //
  // We mean it.
  //
  //
  
  #include "private/qobject_p.h"
  #include "QtCore/qstack.h"
  #include "QtCore/qset.h"
  #include "QtCore/qhash.h"
  
  QT_BEGIN_NAMESPACE
  
  class QPersistentModelIndexData
  {
  public:
      QPersistentModelIndexData() : model(0) {}
      QPersistentModelIndexData(const QModelIndex &idx) : index(idx), model(idx.model()) {}
      QModelIndex index;
      QAtomicInt ref;
      const QAbstractItemModel *model;
      static QPersistentModelIndexData *create(const QModelIndex &index);
      static void destroy(QPersistentModelIndexData *data);
  };
  
  class Q_CORE_EXPORT QAbstractItemModelPrivate : public QObjectPrivate
  {
      Q_DECLARE_PUBLIC(QAbstractItemModel)
  
  public:
      QAbstractItemModelPrivate() : QObjectPrivate(), supportedDragActions(-1), roleNames(defaultRoleNames()) {}
      void removePersistentIndexData(QPersistentModelIndexData *data);
      void movePersistentIndexes(QVector<QPersistentModelIndexData *> indexes, int change, const QModelIndex &parent, Qt::Orientation orientation);
      void rowsAboutToBeInserted(const QModelIndex &parent, int first, int last);
      void rowsInserted(const QModelIndex &parent, int first, int last);
      void rowsAboutToBeRemoved(const QModelIndex &parent, int first, int last);
      void rowsRemoved(const QModelIndex &parent, int first, int last);
      void columnsAboutToBeInserted(const QModelIndex &parent, int first, int last);
      void columnsInserted(const QModelIndex &parent, int first, int last);
      void columnsAboutToBeRemoved(const QModelIndex &parent, int first, int last);
      void columnsRemoved(const QModelIndex &parent, int first, int last);
      static QAbstractItemModel *staticEmptyModel();
      static bool variantLessThan(const QVariant &v1, const QVariant &v2);
  
      void itemsAboutToBeMoved(const QModelIndex &srcParent, int srcFirst, int srcLast, const QModelIndex &destinationParent, int destinationChild, Qt::Orientation);
      void itemsMoved(const QModelIndex &srcParent, int srcFirst, int srcLast, const QModelIndex &destinationParent, int destinationChild, Qt::Orientation orientation);
      bool allowMove(const QModelIndex &srcParent, int srcFirst, int srcLast, const QModelIndex &destinationParent, int destinationChild, Qt::Orientation orientation);
  
      inline QModelIndex createIndex(int row, int column, void *data = 0) const {
          return q_func()->createIndex(row, column, data);
      }
  
      inline QModelIndex createIndex(int row, int column, int id) const {
          return q_func()->createIndex(row, column, id);
      }
  
      inline bool indexValid(const QModelIndex &index) const {
           return (index.row() >= 0) && (index.column() >= 0) && (index.model() == q_func());
      }
  
      inline void invalidatePersistentIndexes() {
          foreach (QPersistentModelIndexData *data, persistent.indexes) {
              data->index = QModelIndex();
              data->model = 0;
          }
          persistent.indexes.clear();
      }
  
      /*!
        \internal
        clean the QPersistentModelIndex relative to the index if there is one.
        To be used before an index is invalided
        */
      inline void invalidatePersistentIndex(const QModelIndex &index) {
          QHash<QModelIndex, QPersistentModelIndexData *>::iterator it = persistent.indexes.find(index);
          if(it != persistent.indexes.end()) {
              QPersistentModelIndexData *data = *it;
              persistent.indexes.erase(it);
              data->index = QModelIndex();
              data->model = 0;
          }
      }
  
      struct Change {
          Change() : first(-1), last(-1) {}
          Change(const Change &c) : parent(c.parent), first(c.first), last(c.last), needsAdjust(c.needsAdjust) {}
          Change(const QModelIndex &p, int f, int l) : parent(p), first(f), last(l), needsAdjust(false) {}
          QModelIndex parent;
          int first, last;
  
  
          // In cases such as this:
          // - A
          // - B
          // - C
          // - - D
          // - - E
          // - - F
          //
          // If B is moved to above E, C is the source parent in the signal and its row is 2. When the move is
          // completed however, C is at row 1 and there is no row 2 at the same level in the model at all.
          // The QModelIndex is adjusted to correct that in those cases before reporting it though the
          // rowsMoved signal.
          bool needsAdjust;
  
          bool isValid() { return first >= 0 && last >= 0; }
      };
      QStack<Change> changes;
  
      struct Persistent {
          Persistent() {}
          QHash<QModelIndex, QPersistentModelIndexData *> indexes;
          QStack<QVector<QPersistentModelIndexData *> > moved;
          QStack<QVector<QPersistentModelIndexData *> > invalidated;
          void insertMultiAtEnd(const QModelIndex& key, QPersistentModelIndexData *data);
      } persistent;
  
      Qt::DropActions supportedDragActions;
  
      QHash<int,QByteArray> roleNames;
      static const QHash<int,QByteArray> &defaultRoleNames();
  };
  
  QT_END_NAMESPACE
  
  #endif // QABSTRACTITEMMODEL_P_H
  